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filter is not described

comment_save_pre filter-hook . WP 1.5.0

Filters the comment content before it is updated in the database.

Usage

add_filter( 'comment_save_pre', 'filter_function_name_102' );
function filter_function_name_102( $comment_content ){
	// filter...

	return $comment_content;
}
$comment_content(string)
The comment data.

Where the hook is called

wp_update_comment()
wp-includes/comment.php 2206
$data['comment_content'] = apply_filters( 'comment_save_pre', $data['comment_content'] );

Where the hook is used (in WP core)

wp-includes/default-filters.php 117
add_filter( $filter, 'convert_invalid_entities' );
wp-includes/default-filters.php 118
add_filter( $filter, 'balanceTags', 50 );